Implanted Temperature Sensor And Weak Current Readout Circuit

With the development of integrated circuit processing technology and biomedical sensors, it make the biomedical sensor to be miniature,low power and wireless. The implanted biomedical devices come to people.it promote the development of medical electronics. This thesis will descript the design of a temperature sensor and a current readout circuit.Firstly, after analyze the principle of incremental Sigma Delta analog to digital converter, use inverter-based OTA to realize low power Sigma Delta modulator. Secondly, analyses the principle of the CMOS integrated temperature sensor, influence of various non-ideal factors of temperature sensor circuit. Then through chopper technology, dynamic element match technology, reduce the effect of offset> mismatch and flick noise so as to improve the consistency of the circuits. A lot of operation in the digital domain to reducing the switch in analog domain.This work realizes temperature sensor and weak current readout circuits, solves the problem of mismatch, offset, flicker noise and so on. The simulation result shows the error of temperature sensor without calibration is less than 0.2℃ and the current readout error is less than 100pA.The total current consumption is 5μA.Compared with the similar design, this work has advantage of low power and good consistency of process.